Numerical simulation of three-dimensional unsteady flows in turbomachines

These viscous and compressible fluid flows are three-dimensional and unsteady: so they are governed by the full Navier-Stokes (N.S.) equations. Numerical methods solving these equations are being developed, and their applications are limited at the present time. Therefore some simplifications of the N.S. equations are now used; they are given by the physical analysis of the real phenomena and turn on the following topics: splitting the 3-D flow into two 2-D flows (axisymmetric meridian flow and blade-to-blade flow); viscous effects neglected or simply modelled (Euler methods); unsteady phenomena mainly produced by blade-row interactions, approached by taking a small number of each blade-row passages into account.